Sleep apnea is a breathing disorder characterized by brief disruptions of breathing during sleep. When a person stops breathing during sleep due to sleep apnea, the balance of oxygen and carbon dioxide in the blood is upset. This imbalance stimulates the brain to restart the breathing process. The brain signals the person to wake up so that the muscles of the tongue and throat can increase the size of the airway, by allowing carbon dioxide to escape and oxygen to enter the airway. These waking episodes are necessary to restart breathing, disrupt sleep, and may cause daytime exhaustion.
There are two types of sleep apnea: central and obstructive. Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA). OSA is the most common type of sleep apnea. It is caused by a breathing obstruction, which stops the airflow in the nose and mouth. CSA is less common than OSA, and is manifested as a central nervous system disorder that occurs when the brain signal telling the body to breathe is delayed. CSA can be caused by disease or injury involving the brainstem, such as a stroke, a brain tumor, a viral brain infection, or a chronic respiratory disease.
While the causes of apnea are different in CSA and OSA, the symptoms and results are generally similar, namely a deprivation of oxygen and poor sleep. The treatments for CSA include medications that stimulate the need to breathe and administration of oxygen. As used herein, sleep apnea includes either CSA or OSA.
Normally, the muscles of the upper part of the throat keep the airway open to permit airflow into the lungs. When the muscles of the upper airway relax and sag, the relaxed tissues may vibrate as air flows past the tissues during breathing, resulting in snoring.
When a person has OSA, the throat collapses during sleep, blocking the airway and preventing air from getting to the lungs. Generally, the throat muscles keep the throat and airway open. The resulting effect of OSA could become serious.
Exemplary sleep apneas treatment devices are described in the following publications: U.S. Pat. Nos. 4,655,213; 5,176,618; 5,238,006; 5,466,193; 7,353,826; 7,481,224; 7,487,777; 7,578,013; 7,578,294; 7,581,542; and D589140. Although several treatment devices have been described, the most common devices are classified into three categories: CPAP; dental appliances, oral devices, and lower jaw adjustment devices; and surgery.
CPAP (Continuous Positive Airway Pressure) is widely recommended for moderate to severe obstructive sleep apnea. CPAP entails wearing a mask-like device (or nose pillows) during sleep, in order to provide continuous, positive, pressurized air to prevent the airway from collapsing. While CPAP has proven to be effective for numerous patients, many people find the apparatus uncomfortable and awkward to use, particularly due to air leaks at higher pressures. Some improvements to the CPAP technology include options such as: “bilevel PAP,” which switches from higher to lower air pressure during the expiration; and “AutoPAP”, which uses an internal regulator that adjusts pressure rather than remaining at one fixed setting. Nonetheless, CPAP, as its name indicates, still uses “continuous” positive pressure.
Dental appliances, oral devices, and lower jaw adjustment devices may be made of acrylic and fit inside the mouth. Two oral devices that are commonly used are the mandibular repositioning device and the tongue retaining device. These oral devices open the airway by bringing the lower jaw or tongue forward during sleep. While oral devices are more convenient to use than CPAP, they are generally more effective for mild to moderate sleep apnea cases. A number of side effects may result from the use of the dental appliances, such as soreness, and damage to, or permanent change in position of the jaw, teeth, and mouth; saliva build-up; and nausea.
Surgery can increase the size of the patient's airway. The surgeon may remove tonsils, adenoids, or excess tissue at the back of the throat or inside the nose. The surgeon may reconstruct the jaw to enlarge the upper airway. Surgery may be an effective option for some patients; however, surgery carries the risks of surgical complications and infections.
While the foregoing treatment devices are useful for their intended purposes, there remains an unsatisfied need for a simple, cost-effective device, system, and method for reducing sleep disordered breathing events.